1. Field of the Invention
The present invention relates to a method and an apparatus for supplying compressed gas to a point of use. More particularly, the invention relates to an acetylene distribution system that fills a transportable source of gas that can be located at a worksite, used and then removed and replaced by another transportable source.
2. Description of the Related Art
Compressed fuel gases, especially gases such as acetylene, are well known and widely used in construction and manufacturing. Typically, acetylene is mixed with oxygen at a point of use to provide a combustible mixture. Because of its volatility, acetylene must be carefully handled before and during use. Conventionally, acetylene is provided at a point of use in a cylinder that can be delivered and then removed and refilled.
In addition to simple welding operations requiring a single cylinder, there are many operations that make use of large amounts of acetylene, making the use of a single cylinder at a time impractical. In these instances, several cylinders can be used in combination with a manifold to provide a constant source of acetylene to an operation. In one prior art arrangement, cylinders are delivered to the worksite connected together with a manifold and, with the use of equipment to regulate pressure, used to provide regulated acetylene to an operation. More recently, cylinders have been arranged on a trailer and then used at a site while remaining on the trailer. This approach eliminates the unloading and reloading of the cylinders at the point of use, and consequently makes it easier to replace empty cylinders with filled cylinders.
Typically, the trailer is taken to an acetylene supply plant to fill the cylinders with acetylene. The acetylene plant consists of a trailer filling system that connects to the manifold on the trailer to facilitate the filling of the cylinders. In a conventional filling system, multiple trailers are filled simultaneously. However, due to the chemical characteristics of acetylene, the filling process slows down as trailers get close to being filled. Specifically, acetylene cylinders accept gas at a progressively lower rate due to exothermic heat buildup increasing partial pressures of the acetylene/solvent mix within the cylinder. Therefore, in conventional filling systems, the typical approach is to fill trailers in parallel and then let them cool, often overnight, and subsequently finish the filling process the following morning. Thereafter, a few cylinders are removed from the trailer, weighed, and the total weight for the trailer is extrapolated. This intermittent filling procedure is non-conducive to acetylene suppliers that typically make and supply acetylene on a continuous round-the-clock basis.
After the cylinders are filled with acetylene, the trailer transports the acetylene to a worksite requiring acetylene gas. Pressure regulating equipment is connected to the trailer to discharge the acetylene from the cylinders. The pressure regulating equipment is typically secured in one location, thereby limiting the supply of acetylene to one specific area of the worksite. Therefore, if acetylene is required at another location, the acetylene gas is transported through an extensive piping arrangement. The use of pipes to transport acetylene to a new location on a worksite can be very costly and creates delays due to piping construction time along with safety concerns due to the volatility of acetylene.
There is a need, therefore, for a method to safely and economically fill acetylene into cylinders on a trailer. There is a further need to safely and economically transport acetylene to a worksite. There is yet a further need for a transportable acetylene distribution apparatus that provides a simple and flexible way to provide and use large volumes of compressed acetylene at a worksite.